I need to install java on my linux server, but I am not getting the exact instruction how to do it. Actually I want to integrate icici payment gateway in my website. For that java need to be installed.

You can search your query on Google you will get exact information about your problem. I am not aware of this kind of payment integration because I am using merchantinc.com which is one of the most secure and merchant friendly payment gateways provides best service to the customers.